OK. Mystery solved. After much frustration I've learned that yes, indeed, the RH detent is the same part; however, the RH safety itself is not identical to the Shadow 1. After trying the RH safety that came with the extended safety on my Shadow 2, I saw that it is in fact a thicker part. The RH safety of the Shadow 2 reaches deeper inside the frame when compared to the Shadow 1's RH safety. Once I used the RH safety that came with the gun things went back together as expected.
Thanks for the help everyone.